polish the code a little bit

Author: chenghao-intel

sql/core/src/main/scala/org/apache/spark/sql/SQLContext.scala

@@ -193,7 +193,7 @@ class SQLContext(@transient val sparkContext: SparkContext)
     }
   }
 
-  protected[sql] def parseSql(sql: String): LogicalPlan = ddlParser(sql, false)
+  protected[sql] def parseSql(sql: String): LogicalPlan = ddlParser.parse(sql, false)
 
   protected[sql] def executeSql(sql: String): this.QueryExecution = executePlan(parseSql(sql))
 
@@ -207,8 +207,6 @@ class SQLContext(@transient val sparkContext: SparkContext)
   @transient
   protected[sql] val defaultSession = createSession()
 
-  // Sub class may need to overwrite the following 2 functions custom sql dialect parser support
-
   protected[sql] def dialectClassName = if (conf.dialect == "sql") {
     classOf[DefaultDialect].getCanonicalName
   } else {

sql/core/src/main/scala/org/apache/spark/sql/sources/ddl.scala

@@ -38,7 +38,7 @@ private[sql] class DDLParser(
     parseQuery: String => LogicalPlan)
   extends AbstractSparkSQLParser with DataTypeParser with Logging {
 
-  def apply(input: String, exceptionOnError: Boolean): LogicalPlan = {
+  def parse(input: String, exceptionOnError: Boolean): LogicalPlan = {
     try {
       parse(input)
     } catch {

sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/SQLQuerySuite.scala

@@ -18,6 +18,7 @@
 package org.apache.spark.sql.hive.execution
 
 import org.apache.spark.sql.catalyst.analysis.EliminateSubQueries
+import org.apache.spark.sql.catalyst.errors.DialectException
 import org.apache.spark.sql.DefaultDialect
 import org.apache.spark.sql.{AnalysisException, QueryTest, Row, SQLConf}
 import org.apache.spark.sql.hive.MetastoreRelation
@@ -256,7 +257,7 @@ class SQLQuerySuite extends QueryTest {
     getSQLDialect().getClass === classOf[HiveQLDialect]
 
     sql("SET spark.sql.dialect=MyTestClass")
-    intercept[Exception] {
+    intercept[DialectException] {
       sql("SELECT 1")
     }
     // test if the dialect set back to HiveQLDialect